The present invention generally relates to alloys of uranium, and, more particularly to ternary alloys of uranium, vanadium and niobium.
Binary alloys of uranium and vanadium are described in U.S. Pat. No. 5,963,777 issued to Michael Staker and which is incorporated by reference herein. U.S. Pat. No. 5,963,777 describes the making and usefulness of the alloys; whereas, the science of the alloys system is described in a journal article by M. R. Staker, J. Alloys and Compounds 266, 167 (1998). Distinctions between binary alloys of U.S. Pat. No. 5,963,777, consisting essentially of pure vanadium and uranium, and earlier alloys of uranium and vanadium from the 1950""s, which had greater carbon contents, are described in the journal article. This difference between essentially pure uranium-vanadium binary alloys and the uranium-vanadium-carbon ternary alloys is discussed in the review of the new uranium-vanadium phase diagram by J. F. Smith in J. Phase Equilibria 19, No. 6, 603 (1998) and in another publication, a book, xe2x80x9cDesk Handbook: Phase Diagrams for Binary Alloysxe2x80x9d edited by H. Okamoto, an ASM Publication (2000) on page 773. In both publications, the corrections to the phase diagram are carefully considered. Carbon, in older alloys, was in the range of 100 to 1000 weight parts per million (Wppm) and was an unintentional alloying contaminate that caused the old binary phase diagram to be in error. Before this discovery, ternary alloys of uranium-vanadium-carbon were mistakenly thought to be binary alloys of uranium-vanadium. The new phase diagram research has shown carbon to be a significant alloying ingredient and has set limits on the amount of carbon allowed (as a contaminate) in order for the alloy to behave as a simple binary alloy, generally about 100 Wppm. The new phase diagram has also allowed the true uranium-vanadium binary alloys system (without large percentages of carbon) to be utilized and exploited. In alloys of uranium-vanadium where the carbon level is above 100 weight parts per million (Wppm) the carbon acts as a major alloying element, resulting in a uranium-vanadium-carbon ternary alloy, and affecting the phase diagram and most other metallurgical properties.
Other uranium alloys include either binary alloys of uranium, with elements other than vanadium; or polynary alloys, that contain other elements, as main alloying elements. Examples include uranium-titanium, uranium molybdenum, uranium-titanium-hafnium (such as in LaSalle et al, U.S. Pat. No. 4,935,200), and uranium-titanium-vanadium (such as in Hemperly, U.S. Pat. No. 3,969,160). These suggest a general trend of increasing hardness and strength as additional elements are added to the alloys. General principles of metallurgy and examples taken from these polynary uranium alloys suggests that the addition of further alloying elements increases the hardness and decreases the machinablity of the alloys as additional elements are added. For some purposes it may be desirable to utilize uranium alloys with improved machinability properties.
The invention is a family of alloys of uranium, vanadium and niobium or a composition of matter hereafter also known as stakalloy having compositions in the ranges comprising 1.0 to 4.5 percent by weight vanadium, 0.01 to 0.95 percent by weight niobium, and the balance being uranium. These alloys may be solutionized and quenched. They may also be aged.